Plaid valve covers

[SkipStein]

Howdy;
I owned a 1963 GMC Carry All 4x4, 4 speed with a Big Block 305 V6. The engine had the 'plaid' valve covers. Concerning the why's of the plaid valve covers, the story I heard was that at the factory they pulled an engine off the line periodically to tinker with it and check the tolerances, etc. When finished, it was 'blue printed' and put back on the line with the 'plaid' valve covers. Mine was a real stump puller and ran strong. I pulled the heads off at 242K to replace the gaskets and checked the bore and valves, etc. It was less than 10 thousandth wear. I went ahead and bored it 10 thousandths to 315 cu in., replaced the valves, put it back together and it ran another several years as my daily driver and trail buster. A fine truck, for sure...
Happy trails,
Skip

[6066gmcguy]

There have been many stories told about the Plaid Covers, they were Dealer Installed.

In 1963, the Plaid Covers were sent to the dealers to install on trucks in the showroom or the demo trucks. Then when a customer would ask about them, they would be told how the NEW 305E was better over the older 305D engine, fuel economy was one the selling points, "Thrifty as a Scott!", you see back in 1963 stereotyping was still OK.

As the trucks got sold the covers were not pulled off.

The following is told by Bob Bray;

There was some discussion on the 305 plaid valve covers. They had long been a big mystery to me as well, but I think I may have stumbled on an explaination some time ago. I was talking to a retired G.M.C. truck engineer (I think it was Don Meyer that I heard this story from!) who worked all through the 1960's and I asked him about those colorful valve covers and if they really ment anything. He said that as you know, the V-6 had a reputation of not being an economical engine. Many light truck customers, particularly those who had bought early 305A 1bbl. pickups, were not pleased with the fuel economy. G.M.C. sought to improve the economy of the 305 in light duty trucks, and was dyno-testing 305's with different carburetion and camshafts. Engineers in the dyno lab identified the improved engines by putting adhesive shelf paper on the valve covers, and wouldn't you just know it, 'Scotch Plaid' was what they were using. One day, some guys from marketing saw these engines being tested, and though it would be a great marking idea to actually build them that way.

So that kinda backs up the story about them being a marketing thing to sell trucks.

But now many years later, the covers can be found on years other then 1963, and many owners have found th covers and installed them on their own truck, and like myself, I had 3 sets, two have been made into wall art, and a Valve Cover Racer.

[6066gmcguy]

Some Plaid Cover Photos.

[SkipStein]

Hello;
The version of the 'plaid valve covers' mentioned by Bob Bray seems to be in the same direction of the story I heard, as in engines tweeted and tested, blue printed and put back on the line. I never heard of the story of the dealers and marketing, but that may make sense also. Never the less, the 305 E engines were good runner, at least in my '63 Carry All.

[jimjaz]

The story I heard from my brother-in-law who worked at GM for over 40 years told me the following about the plaid valve covers;
1) They were never offered already on the trucks from the factory.
2) They were made at the factory and sent to GMC dealers.
3) Folks who bought a 1963 model would bring their truck in for "valve train noise" under warranty. The dealer would adjust the solid lifter tappet valve train to spec's, and to identify the truck as having been serviced and the valve train adjusted, the owner coached on the differences in solid vs hydraulic valve train, and the added plastic "plaid" over metal quiets down the tappet noise as plastic is a pretty fair noise insulator in this situation.
4) He did not know why this did not continue into the 64 model and beyond, but this is why they are only correct for a 63 model truck.

For what it's worth.....

[David R Leifheit]

Originally Posted by jimjaz

The dealer would adjust the solid lifter tappet valve train to spec's, and to identify the truck as having been serviced and the valve train adjusted, the owner coached on the differences in solid vs hydraulic valve train, and the added plastic "plaid" over metal quiets down the tappet noise as plastic is a pretty fair noise insulator in this situation.

For what it's worth.....

Considering the material isn't really plastic and is more like shelf paper, I doubt it would contribute to "quiet" much if at all.

[6066gmcguy]

Everyone wants their story of the Plaid covers to be the one that is true, but the truth is it was all about Sales.

I don't have a working scanner so I just shot some pics with my phone, check out the info below and then come up with some more reasons why your story it more true than the next guys, but unless you have the paper trail to back it up, its just another story.

[Justinfleenor]

Hi I'm new here I've got a 68 with a 305 e and I had a 65 with chrome or just plain metal valve covers didn't appear that anyone sanded the paint off lol and the truck was purchased from a woman when it was almost new by my grandfather, has anyone seen any?

[bigblockv6]

As far as chrome valve covers, there were some engines with chrome valve covers for promotional display purposes. Ed Snyder can fill anyone in on this with his fathers 65 Suburban that has dealer installed 351C with chrome valve covers.

[Ed Snyder]

Originally Posted by bigblockv6

As far as chrome valve covers, there were some engines with chrome valve covers for promotional display purposes. Ed Snyder can fill anyone in on this with his fathers 65 Suburban that has dealer installed 351C with chrome valve covers.

My Dad (who turned 91 on Pearl Harbor Day) spent a lot of time at the GMC dealership in Wichita (Sauder-Lygrisse) in 1965 when he was in the process of ordering, taking delivery, and modifying the one ton Suburban. He became friends with the owners during the process. They gave him the chrome valve covers and oil cleaner housing you can see in this photo. If I remember right, they came off a showroom truck that had been sold. So they've been on the truck for 50 years now.